You're only as big as your last hit, they say in show business. Ask any number of former titans in front of or behind the camera who struggle to get decent scripts or gigs these days.

After Apocalypse Now and The Godfather series made Francis Ford Coppola one of the most lauded directors alive in the 70s, he's barely worked over the last couple of decades. Has anyone seen Twixt? Tetro? Distant Vision, which doesn't even appear to have poster art?

He's currently putting his longtime passion project Megalopolis together, which is great for him (and hopefully us), but the industry moved on, and unless Coppola ever wanted to direct Marvel's Captain CGI Part IV there hasn't really been a place for him in modern Hollywood.

You'd think the studios and greenlight executives (especially the older ones who actually know and love movies), are dying for any chance to use the the elder statespeople of the industry who have proven track records.

Maybe it's a cost issue when there are armies of music video directors and YouTubers lined up and willing to work for peanuts just for a seat at the table.

But I'm actually talking about the opposite phenomenon in this Filmism.net Dispatch, where artists keep getting work without appearing to even warrant it. Two of them them in particular occur to me whenever I find myself musing about this issue.

The first is Chris Hemsworth. Now, I know how beloved he is to movie fans. And this is something that's been brewing since long before his recent intention to step back in his career because of the increased risk of Alzheimer's disease he discovered while making a TV show.

Nor does it have anything to do with his talent. But imagine Marvel, Thor and the Avengers had never existed and take another look at his cinematic oeuvre.

The Cabin in the Woods was a cool movie, but he didn't have a real lot to do in it. The Red Dawn remake was a damp squib, a victim of studio politicking and pretty toothless to boot. He oozed charisma in Rush and Bad Times at the El Royale but they were both middling at best.

Blackhat was completely hatstand (as was he in it). He tried his darnedest in the Ghostbusters reboot but none of the comic talent in front of the camera could have rescued that.

Men In Black: International was corporate big studio claptrap. Extraction was big dumb meatheaded and forgettable fun where he did nothing but run, shoot and scowl from behind cool shades, and although Hemsworth has a sense of humour, extended cameos in Vacation and Jay and Silent Bob Reboot didn't do him any favours.

The point is, the guy might be a good actor (though I'd argue we haven't seen him in anything that stretches him far enough for us to judge that yet), but he's pretty poor at picking projects. Yet he's a megastar. Why?

Another name that applies here is Samuel L Jackson. He's been in plenty of turkeys (though that might be the law of averages; he's been in about nine thousand films). But even though Jackson's a firmly established A lister has he ever been a really, really good actor?

Now, when it comes to Hemsworth it has to be said that I'm a straight male, so while I understand all the jokes about how he makes women faint and swoon I'm not the one he makes weak at the knees. Is sheer sex appeal enough to sustain an acting career?

I'm joking. Of course it is. The entire industry was built on and continues to be sustained by sex appeal rather than talent. Look no further than Keanu Reeves. The recent flap over Matthew Perry's tastelessly comparing several great and deceased actors to Reeves notwithstanding, you can't objectively say the guy's a good actor.

But lets turn to another name (and the mechanics of stardom don't apply here because directors aren't sex symbols) in Bob Zemeckis.

The Back to the Future trilogy, Forrest Gump, Who Framed Roger Rabbit and Contact will (and should) buy any director an awful lot of cachet and goodwill in Hollywood. They quite rightly earned Zemeckis a seat at the biggest of big tables.

But here's the thing. Scorsese's last great studio film was Cape Fear , which was 1991. When he wanted to make his new gangster epic in The Irishman, none of the studios would give him the money. He had to go to Netflix. Another hallowed name, David Fincher, had to do the same to make Mank.

Peter Jackson ushered in a new age by showing audiences and studios what epic fantasy could look like, and how successful it could be. But where's his career now? I'm sure he still has a lot of pull, but who'd finance the Lord of the Rings again (except for another streaming service, who indeed has)?

By contrast Bob Zemeckis still keeps making studio movies, routinely in the $50-100m range. But look at his most recent output. Pinocchio for Disney Plus, critically reviled and already forgotten, especially in the face of a competing Pinocchio film that has a far more hand-made, labour-of-love quality from Guillermo Del Toro.

The Witches, which didn't even get a proper release. Welcome to Marwen, which flopped catastrophically. Allied, which was twee and syrupy and barely made money. The Walk, which barely made money and the first half of which was completely disposable. Flight, which was a midday melodrama with a few scenes of good visuals. Beowulf, a circus of CGI and a financial flop.

You could argue Zemeckis hasn't made a really good movie since Cast Away, and that was already 22 years ago. If that's too subjective for you, you could instead argue that barely any of his movies have made money since then. Flight made a truckload but I'd contend that was because of Denzel Washington, not Zemeckis.

The names Hemsworth and Zemeckis are just two for whom the axiom 'you're only as big as your last film' resolutely don't apply. But despite their records their careers are assured, while moviemakers with real art to their names like Coppola, Scorsese or Fincher are finding themselves locked out of the party.

Clearly, as William Goldman once wrote about Hollywood, nobody knows anything.

On screens now, Zoe, a sci fi romance that's fairly light on the philosophy of artificial intelligence/synthetic humans but nevertheless beautiful and has some great ideas.

I was also blown away by the slow burning, heart-in-your-throat Locke, a drama with nothing whatsoever happening on screen except a guy driving a car. Tom Hardy keeps it low key and a series of increasingly fraught phone calls provide all the drama you need and make it an essential watch.

I also continued my love/only-kind-of-like relationship with the films of Jordan Peele. UFO thriller Nope has some great visual ideas and their execution is the kind of cinema we don't see enough any more, evoking some of the movie spectacles of the Spielberg era, but once again, his plot is too evasive to get a satisfying hold on.